Electric piano-player with damping device.



I. F. KELLY.

ELECTRIC PIANO PLAYER WITH DAMPIIIG DEVICE.

APPLICATION FILED JUNE 4.1924.

1,1 84,244. Patented May 23, 1916.

2 SHEETSSHEET I.

WITNESSES: I N VENTOR.

awn/mm BY 4% A TTOR NE Y.

J. F KELLY.

ELECTRIC PIANO PLAYER WITH DAMPING DEVICE.

APPLICATION man JUNE 4.1914.

1,184,244. 5 Patented May 23,1916.

2 SHEETS-SHEET 2.

- M51772 flrzg ATTOR NE Y.

JOHN F. KELLY, 0F PITTSFIELD, MASSACHUSETTS.

ELECTRIC PIANO-PLAYER WITH DAMPING DEVICE.

Specification of Letters Patent.

Patented May 23, 1916.

Application filed June 4, 1914. Serial No. 842,990.

To all whom it may concern:

Be itknown that I, JOHN F. KELLY, a citizen of the United States of America, residing at Pittsfield, in the county of Berkshire and State of Massachusetts, have invented certain new and useful Improvements in Electric Piano-Players with Damping Devices, of which the following is a specification.

This invention relates to improvements in mechanically operated pianos or other musical instruments, and particularly in devices for varying the rate of movement of the keys of the piano. When the instrument is manually operated, the pianist can depress a key firmly but gently throughout its full extent of movement, thus combining the two qualities of firmness and gentleness of touch. When, however, a piano key is mechanically operated, as by a magnet system, and an attempt is made to go below a certain lightness of touch by reducing the current stren th, the armature of the magnet affecte by this reduction of current strength will not 'move throughout its full range or travel. The present invention is, therefore, designed to overcome this difliculty and cause the armature of the electro-magnet to move through its full extent or travel without decreasing its pull and, at the same time, in a manner similar to the combined firm and gentle touch of the pianist.

One form of the present invention consists in placing a-secondary coil on the operating magnet of the instrument which coil is closed on itself through a variable resistance that is connected to a source of electrical energy of constant potential. The result of this construction is that the ultimate magnetic strength of the magnet or the final magnetization of the magnet will be always the same, but the time required to reach this ultimate strength will be longer, depending upon the secondary coil, increasing as re sistance is cut out of the secondary winding or circuit. The result, therefore, is that the armature can always move through its 4 full path, but the time of its motion is varied, so that a damping effect is produced on the-operating devices of the instrument.

It is equally clear that the same result can be obtained by interposing a variable reactance coil in the primary winding of the electro-magnet which operates the key devices of the instrument, and thus be made to fur? nish the same results provided, however, that the resistance of this coil be so low as not to greatly affect the ultimate value of the magnetizing current. It is also clear that the well known dash-pot can be employed to accomplish the same results for retarding or damping the motion of the operating devices without finally arresting their movements. It is also clear that a second pneumatic device can be employed in connection with the well-known pneumatically operated instruments for producing a damping effect upon the operating devices of the instrument.

Referring to the drawings forming a part of the specification-Figure 1 is a view showing the general arrangement of connecting the armature of an electro-magnet to the key or operating device of the piano. Fig. 2 is a diagrammatic view showing the operating electro-magnet, provided with two windings thereon, a portion of a trackerbar over which the note-sheet passes, a source of electrical energy with connections therefrom to the primary windings and a variable resistance in the secondary winding. Fig. 3 is a view, similar to Fig. 2, with the secondary winding omitted and a variable reactance coil in the circuit of the magnet windings. Fig. 4 is a view similar to Figs. 2 and 3, showing the two magnet windings; in the circuit of the primary is interposed a variable reactance coil and in the circuit of the secondary is interposed a variable resistance. Fig. 5 shows a modification in which a dash-pot is combined with the armature to vary the time of its movements. Fig. 6 is a detail view of the cover of the dash-pot. Fig. 7 is a view showing automatic means for varying the number of active turns of the 'reactance and resistance coils. Fig. 8 is a view showing the use of a second pneumatic to produce the damping efiect. Fig. 9 is a detail view of the valve for varying the flow of air from the dampin pneumatic.

eferring to the drawings in detail, 1 designates, in this instance, the keys of a piano or other musical instrument which are connected by means of the rod 2 to the armature 3 of the operating electro-magnet, the poles of whichare conventionally shown at 4 and are connected together by thepole-piece 5. The track-bar is indicated at 6 over which the perforated note-sheet 7 passes,

8 designates a source of electrical energy of constant potential, to one terminal of which is connected the wire 9 that leads to the track-bar, to the opposite terminal of which is connected the wire 10 that extends to the terminal 11 of the primary winding 12. The other terminal 13 of the winding 12 is connected to the wire 14L that co-acts with the perforation in the note-sheet and the tracker-bar to complete the circuit. This is, in general, the usual construction.

Coming now more particularly to the details of the present invention, 15 is a secondary winding on the cores of the magnet, the terminal 15 of which is connected to variable resistance 16 with the coils of which a slidable contact 17 engages. Connected to this contact is a wire 18 that leads to the other terminal 19 of the secondary winding. The inner ends or terminals of the two secondary windings are connected together by means of the wire 20 at the points 21 and 22. It is clear from the well-known laws of electromagnetic induction that, when the circuit is closed through the primary coils 12 at the tracker-bar by means of the notesheet 7, the secondary or reverse current generated in the secondary winding 15 will act to delay the cores of the magnet from assuming their full magnetic strength in the same time as if these secondary windings or coils were not employed, or, in other words, the pull of the armature 3 on the keys of the piano is slowly started and slowly continued to the end of its travel and with a steady and even motion, thus producing substantially the same effect as the gentle and firm touch of the pianist.

The use of the variable resistance 16 provides a very simple means of varying and controlling the strength of the magnetizing current in the primary winding, as'readily understood, and it is, therefore, apparent that the secondary winding serves only for the purpose of delaying the final or ultimate magnetization, so decreasing the speed of the armature without lessening its full path.

Fig. 3 shows a modification of the structure shown in Fig. 2 in which the retarded action of the magnet is accomplished without the secondary winding. the same delayed magnetizing effect being obtained by inserting reactance coil 23 in the circuit of the single magnet winding. 24: designates means for varying the effect of this reactance or self-induction coil on the circuit in order to momentarily check the growth of the current in the winding 13. It will be seen that, when the circuit is closed by means of the perforated note-sheet passing over tracker-bar, the coil 23 serves to oppose the rapid rise of the current to its full magnetizing strength in the windings 12 it being understood that the source of electrical energy is of constant potential. The

sudden pull of the magnet on the key of the instrument is, therefore, prevented, and the ultimate strength of the magnet is delayed. until the opposing electro-motive-force of self-induction in the coil 23 has ceased. In order to make the action of the magnet operate at the proper speed, the device 2 1 is employed to vary the opposing effect of this coil on the circuit.

In Fig. 4 is shown the combination of the structures shown in Figs. 2 and 3, in which, in addition to the adjustable resistance 16 being placed in the secondary winding, as shown in Fig. 2, the variable reactance coil 23 shown in the circuit of the single magnet winding 12 is employed. This arrangement allows a still greater retardation of the magnetization. The reactance coil makes the rise of the magnetizing current slower. The secondary coil causes the magnetization to fall behind the current. It will be obvious that extra reactance might be supplied with substantially the same results by winding extra coils on the actuating magnets. In this case, the magnetizing power would remain practically the same.

Fig- 5 shows a mechanical arrangement for retarding the movements of the armature which consists in connecting to the armature 3, by means of a rod, a piston 26 which works in a cylinder 27 provided with a cover 28. Mounted on this cover is a movable plate 29 to open or close more or less of the openings therein for varying the rate at which the air is drawn into or expelled from the cylinder. This construction is the well known dash-pot employed to control the movements of a moving part. Its use here serves to delay the movements of the armature in the same manner as the electrical devices already described and is a means to retard the movements of the armature without any final arresting action on the key.

It is also within the province of my invention to automatically control the variable resistance 16 by means of perforations 30 in the note-sheet 7 which are connected by wires 31 with the electro-magnets 32, the armatures 33 of which are set at difierent po sitions of adjustment with relation to the poles of the magnets, as shown. These armatures are all connected together by means of the link 34., on the end of which is placed the contact piece 17 for engaging the turns of the resistance coil 16. It is clear that, when the circuit is closed to any one of the magnets 32, the contact 17 will be moved depending upon the extent of movement of the particular armature 33, either to cut in or out more or less of the turns of the resistance coil 16 to vary the effect of magnetization of the operating magnets. In the same manner, the effect of the reactance coils 23 in the primary circuit is automatically controlled by means of perforations in the note-sheet 7. 35 designates these perforations which cooperate with the fingers 36 that are connected to the wires 37 which lead to the electro-magnets 38, the armatures 39 of which are set in different positions of adjustment, as shown.- These armatures are all connected together by means of the links 40-and 41 to the slidable contact member 24, whereby upon any one of the magnets 38 being energized the member 24 will be moved to cut in or out more or less of the turns of the reactance coil 23, whereby the magnetization of the operating magnets will be delayed or damped, as already described.

Fig. 8 shows a dampingdevice applied to a pneumatically operated instrument. 42 is the usual operating pneumatic which is connected to the operating key 1 by means of therod 43. 44 is a second pneumatic that is also connected to the same rod 43. 45 is the usual exhaust pipe connection. 46 is a valve by means of whichthe number of operative openings 47 may be varied to vary the damping effect. WVhen the air is exhausted from the pneumatic'42, the external atmospheric pressure will cause the pneu matic to collapse. This movement will be transmitted to the second pneumatic 44 by means of the connecting rod 43. As the pneumatic 42 collapses, the second pneumatic 44 will prevent the same from rapidly moving to a closed position, the rate of the damping being determined by means of the valve 46. By means of this construction, a steady and firm motion will be imparted to the operating devices. It is to be understood that the rod 43 is so connected to the operating key 1 as to move the same in the proper direction for operating the instrument.

The term actuating devices, is to be understood to mean those devices which operate the parts of the instrument which actually produces the musical tones or sounds as, for example, in a piano, the key and those parts of the instrument that are moved thereby for striking the tuned wires are to be understood as referring to the actuating devices as distinguished from the particular member which emits'the musical sound.

What I claim is 1. The combination with the keys of a musical instrument of the kind described, of electro-magnets, armatures connected to the keys, and variable electro-magnetic inductive means to control the rate of movement of the armatures.

2. The combination with the actuating devices of a musical instrument of the kind described, of electro-magnetic devices connected to said actuating devices, adjustable means inductively associated with' the windings of said electro-magnetic devices for retarding the rate of magnetism in said devices, a source of electrical energy, and connections therefrom to the windings.

3. The combination with the keys of an instrument of the kind described, of electro- -magnets, armatures therefor for operating the keys of the instrument, connections from the armatures to the keys, adjustable inductive means associated with the coils of said magnets for controlling the magnetism thereof, a source of electrical energy, and connections therefrom to the windings of the electro-magnets.

4. The combination with the keys of an instrument of the kind described, of electro-magnets, armatures therefor for operating the keys of the instrument, connections therefrom to the keys, at source of electrical energy, electrical connections therefrom to the windings of the magnets, means interposed in the circuits of the windings to produce additional reactances for delaying the effects of the magnetizing current.

5. The combination with the keys of a musical instrument of the kind described, of electro-magnets, armatures therefor, connecti'onsfrom the armatures to the keys of the instrument, a source of electrical energy, electrical connections therefrom to the windings of said magnets, closed secondary windings on the magnets to delay the magnetization for retarding the motion of the armatures when the circuit of said windings is closed, and means for varying the inductive effect of the secondary windings.

6. The combination with the keys of a musical instrument of the kind described. of electro-magnets, armatures for the electro-magnets. connections from the armatures to the keys of the instrument, a source of electrical energy, connections therefrom to the windings of said magnets, closed secondary windings on each of the magnets to delay the magnetization and retard the motion of the armatures when the circuits to said windings are closed, and means in the secondary windings to vary the currents induced therein.

7. The combination with the keys of a musical instrument of the kind described. of electro-magnets, armatures connected to the keys of the instrument, primary and secondary windings on the electro-magnets, a source of electrical energy connected to the primary windings, reactance devices in the circuits of the primary windings, and means in the coils of the secondary windings to vary the currents induced in the said coils.

8. The combination with a musical instrument of the kind referred to, of electro-magnets, armatures therefor, connections from the armatures t0 the operating devices, primary and secondary windings on the electromagnets, a source of electrical energy of constant potential, connections therefrom to the primary windings, variable reactance coils in the circuits of the primary windings, and means in the secondary coils for varying the currents induced in the said coils.

9. The combination with an instrument of the kind referred to, of electro-magnets for operating the instrument, a source of energy for energizing said magnets, branch circuits leading from the source of energy to the magnets, means for closing the branch circuits to the windings of said magnets, and electromagnetic inductive means for retarding the magnetization.

10. The combination with the actuating devices of a musical instrument of the kind referred to, of electro-magnets for operating the said devices, a source of electrical energy for energizing said magnets, eleetromagnetic devices for delaying the operation of the magnetizing current, and means for controlling the operation of said devices.

11. The combination with the keys of a musical instrument of the kind referred to,

Copies of this patent may be obtained for of electro-magnets for operating the same, a source of electrical energy for energizing the electro-magnets, and adjustable reactance coils associated with the windings of the electro-magnets for delaying the operation of the ma netizing current.

12. The com ination with the actuating devices of an instrument of the kind referred to, of electro-magnetic devices to operate the actuating devices, and adjustable means for electro-magnetically retarding the magnetization of said magnetic devices.

13. The combination with the actuating devices of a musical instrument, of electromagnetic devices for operating said devices, inductive means associated with the windings of the electro-magnetic devices for producing a damping or retarding effect upon the magnetization of said magnet.

JOHN F. KELLY.

Witnesses:

HARRY W. BOWEN, CAROLINE W. VILLIS.

flve cent: each, by addressing the Commissioner of Patel. Washington. I. 6. 

